Why did the transatlantic slave trade expand after the 16th century

It is estimated that by the early 16th century as much as 10% of Lisbon's population was of African descent. After the European discovery of the American continent, the demand for African labour gradually grew, as other sources of labour - both European and American - were found to be insufficient.

lincoln presided over the union victory in the american civil war, which dominated his presidency. a former whig, lincoln ran on a political platform opposed to the expansion of slavery in the territories. his election served as the immediate impetus for the outbreak of the american civil war.